1. Technical Field
The present disclosure relates to flat panel display technology.
2. Description of Related Art
Liquid crystal displays (LCDs) have advantages of portability, low power consumption, and low radiation, and thus have been widely used in various portable information products.
A typical LCD includes a backlight module and an LCD panel. The backlight module provides light beams to the LCD panel. The LCD panel includes a color filter (CF) substrate, a thin film transistor (TFT) array substrate, and a liquid crystal layer sandwiched between the two substrates. When the LCD is in operation, an electric field is applied to the liquid crystal layer, and at least some of liquid crystal molecules in the liquid crystal layer change orientation such that the liquid crystal layer provides anisotropic transmittance of light therethrough. By controlling the electric field, the amount of the light beams passing through the color filter substrate can be adjusted, and thereby desired pixel colors can be obtained and a corresponding image provided by the LCD.
The TFT array substrate includes a plurality of parallel gate lines each extending along a first direction, a plurality of common lines alternately arranged with the gate lines, a plurality of parallel data lines each extending along a second direction orthogonal to the first direction, and a plurality of pixel units defined by the crossing gate lines and data lines. In particular, the smallest rectangular area formed by any two adjacent gate lines together with any two adjacent data lines defines a pixel unit thereat. Each of the common lines includes a plurality of storage electrodes, each of which is located in a respective pixel unit. The pixel unit includes a TFT, a pixel electrode, and the storage electrode. The TFT includes a gate electrode connected to the gate line, a source electrode connected to the data line, and a drain electrode connected to the pixel electrode. The pixel electrode, a common electrode of the CF substrate, and liquid crystal molecules therebetween cooperatively form a liquid crystal capacitor. The pixel electrode, the storage electrode of the common line, and medium (such as a passivation layer) therebetween cooperatively form a storage capacitor.
As described, the storage capacitor is formed by the cooperation of the pixel electrode and the storage electrode. In order to ensure that the storage capacitor has good capacitance, the storage electrode occupies a large area. Because the common line is normally metal which is lightproof, the large area of the storage electrode may cause an aperture ratio of the LCD to be low.
What is needed, therefore, is an TFT array substrate that can overcome the described limitations.